Sofa bed hinge structure



March 16, 1948. M. FOX ETAL SOFA BED HINGE STRUCTURE Filed Dec. 8, 19443 Sheets-Sheet l m. a Z2 "2 M. 2 aw 2 Z March 16, 1948. M. FOX ETAL.2,437,949

SOFA BED HINGE STRUCTURE Filed Dec. 8, 1944 3 Sheets-Sheet 2 firzfeii 20715:

. ml/flzdawmaw March 16, 1948. M. FOX EI'AL 2,437,949

SOFA BED HINGE STRUCTURE Filed Dec. 8, 1944 5 SheetsSheet 3 PatentedMar. 16, 1948 SOFA BED HINGE STRUCTURE Martin Fox and George F. Hassel,Chicago, Ill, assignors to The Seng Company, a corporation of IllinoisApplication December 8, 1944, Serial No. 567,149

I 6 Claims.

This invention relates to convertible sofa hinge structures, and moreparticularly to an improved mechanism for transforming a sofa to a bed,or a bed back to a sofa.

The primary object of the invention is to provide an improved structurewhich is practically fool proof in operation. The structure permits asofa to be transformed into abed by merely raising the seat section asfar as it will go, and then lowering it to bed position. To return, itis merely necessary to raise the seat section as far as it will go, andthen press it down to the sofa position. If desired, the seat sectionmay be retained in raised intermediate position, to facilitate access tothe space in the sofa structure beneath the seat.

A further object of the invention is to provide a simple and reliableautomatic disengaging member which is yieldingly urged in one directionby gravity or a spring, and does not require an overbalancing movement.

Another object of the invention is to avoid pin-and-slot connections,and to protect the disengaging tumbler from dirt, lint and bedding.which might interfere with automatic operation.

A hinge structure is preferably provided at each end of the sofa, but asthe mechanism is similar at each end, only one of the hinges is 11-lustrated in the accompanying drawings, in which- Figure 1 is anelevational view of the structure in sofa position; Fig. 2, a similarview in intermediate position; Fig. 3, a view similar to Fig. 2, withthe seat portion fully raised to start release of the pawl; Fig. 4, anelevational view of the structure in bed position; Fig. 5, anelevational view with the seat section being raised from bed positionand the tumbler being reset so that the pawl may be reengaged; Fig. 6,an elevational view of the inside of the transfer pawl; and Fig. "I, asectional view taken as indicated at line 1-1 of Fig. 1, showing thestud to prevent the back of the sofa from tilting forwardly.

In the embodiment illustrated, a metal supporting plate I is providedfor attachment by screws to the main frame la (indicated by dottedlines), of the sofa bed. A back plate 8, which is adapted to be securedto the back section 811 (indicated by dotted lines) of the sofa, isconnected to the supporting plate I by means of a front arm 9, and arear arm Ill, said arms being provided with pivots at each end.

A seat plate II is adapted to be secured by screws to the seat sectionIla (indicated by dotted lines), and is hinged to the back plate 8 by apivot l2, which also serves as the upper pivot for the front arm 9. Atransfer pawl I3 is pivotally connected to the seat plate II, asindicated at ll, and has edge flanges l5 which 2 form a closure, andtumbler member l8, which is pivotally mounted within the transfer pawl,as indicated at IT. The transfer pawl has a rather large notch l8, whichis adapted to engage a small latching finger 19, which may be one leg ofa U-shaped keeper 20, secured to the back plate 8.

The tumbler member l6, which is best shown in Fig. 6, has a shoulderedindentation with an inner carrying portion 2|, and a communicatingthrow-out portion 22, which is partially closed by a lobe or guard 23.The tumbler member has a positioning detent 24 to engage the finger l9and swing the tumbler up into its extreme position in the transfer pawll3, when the seat section is being raised from the position shown inFig. 4, through the position shown in Fig. 5, to its uppermost position.Accordingly, when the notch 18 drops over the finger IS, the lower edgeof the lobe will ride on the finger i9 andhold that portion of thetumbler l6 up above the notch l8. Upward movement of the seat section isarrested by the outer portion of the notch I8 in the pawl by catchingthe finger 19. When the movement of the seat section is reversed, theopposite side of the notch l8, which is undercut, comes into engagementwith the finger l9, and only then can the tumbler drop down so that itscarrying portion 2| engages the finger. It will be seen that onlyanother reversal of the movement of the seat section could bring thethrowout portion 22 into engagement with the finger. It will be notedthat the tumbler I6 is always urged downwardly about the pivot l1, andno overbalancing is required.

It will be seen in Figs. 1 and 6 that the undercut portion of the notchl8 registers with the carrying portion 2| of the tumbler and forms areliable support for the weight of the back section in sofa position.The throw-out portion 22 of the tumbler is undercut with respect to thelobe 23, and registers with the'outer open portion of the notch l8, asshown in Fig. 3, so that the tumbler will readily disengage the transferpawl from the finger when the seat section is lowered from the positionshown in Fig. 3. However, the throw-out portion 22 is only effectivewhen it is in engagement with the finger l9, and it can only enter thethrow-out portion after it has been in the carrying portion 2| of thetumbler.

In order to prevent the back section of the sofa bed from having itstopportion swing forwardly from sofa position, a stud 25 is provided on thesupporting plate I, to be engaged by the rear edge of the arm 9.

A spring 2'6 is tensioned between the front arm 9 and the frame Ia, soas to urge the structure from the sofa position illustrated in Fig. 1towards the intermediate position shown in Fig. 2. The device isself-locking, but the spring facililimits the movement of a i springalso serves to hold the back section and seatsection in the relationshown in Fig. 1, .while beingtransferred to the intermediate position.That is, the spring tension urges the finger 2i against the innerportion ofthe notch I 8 in the pawl, and downward movement of the backsec tion is prevented bysthe pawl except when the seat section israised.

To transform the mechanism from the sofa position illustrated in Fig. 1tothe bed position shown in- Fig. 4, it is merely necessary to raise theseat as high as it will go, which will bring the back section into thebed position shown in Fig. 3, and then lower the seat to the positionshown in Fig. 4. During the movement from the position shown in Fig. 1to the position shown in Fig, 3, the finger l9 shifts from one side ofthe notch ill to the other and permits the throwout portion 22 of thetumbler to drop into position. Upon reversal of movement of the seatsection, the pawl is automatically disengaged by the tumbler. To returnto sofa position, it is merely necessary to raise the seat section ashigh as it will go, and then force it down to the position shown inFig. 1. The detent 24, in moving from bed position, positions thetumbler so that the finger I 9 does not reenter the throw-out portion 22of the tumbler.

The foregoing detailed description is given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, for some modifications will be obvious to those skilled inthe art.

We claim:

1. A convertible sofa bed hinge structure for a back section and a seatsection comprising: a back plate, adapted to be secured to the backsection, and provided with carrying arms for pivotally connecting saidback plate to a supporting frame; a small latching finger fixed to theback plate; a seat plate hinged to said back plate and adapted to besecured to the seat section; a transfer pawl pivotally connected to theseat plate and having a large notch which opens down-' wardly to engagesaid latching finger when said plates are in sofa position, intermediateposition, or between said positions; a disengaging notched tumblerpivotally mounted on said pawl adjacent to said pawl notch, the notch insaid tumbler being shaped to provide an inner shouldered carryingportion to receive the latching finger whenever said finger is receivedby the inner portion of the pawl notch, and said tumbler notch having anouter throw-out portion to receive. the latching finger when said fingeris moved from the inner portion to the outer portion of the pawl notch,said tumbler having an integrally formed guard extending inwardly acrossthe throw-out portion of the tumbler notch towards the carrying portionof the tumbler notch so that the finger can only enter said throw-outportion after it has entered said carrying portion of the tumbler, adetent on said tumbler adjacent to said carrying portion of the tumblernotch and extending downwardly beyond the lower edge of the pawl so asto engage the finger and move the notched portion of the tumbler abovethe pawl .notch when said pawl is returning from disengagedbed-position; and means for urging the notched portion of said tumblerto swing downwardly from all positions of the pawl.

2. Apparatus'as specified in claim 1, in which I the means for urgingthe notched portion of the tumbler to swing downwardly comprises anolfcenter pivotal mounting positioned so that said notched portion isurged downwardly by the force of gravity. 7

3 Apparatus as specified in claim 1, in which the inner portion of thepawl notch is undercut inwardly and spaced from the tumbler pivot thesame distance as the carrying portion of the tumbler, and the outerthrow-out portion of said tumbler, back of the guard, is spaced the samedistance from said pivot as the outer portion of said pawl notch.

4. Apparatus as specified in claim 1, in which the transfer pawl hasflanged edge portions with spaced ends and being turned towards the backplate, and said pawl and flanged portions form ing a housing and stopsfor limiting movement of the tumbler with respect to the pawl.

5. Apparatus as specified in claim 1, in which a tension spring isconnected to one of the carrying arms and the front of the supportingframe so as to urge the back plate from sofa position towardsintermediate position and to urge the latching finger into the latchinginner portion of the pawl notch .when in sofa position and intermediateposition.

6. A convertible sofa bed hinge structure for a back section and a seatsection comprising: a back plate, adapted to be secured to the backsection, and provided with carrying arms for pivotally connecting saidback plate to a supporting frame; a small latching finger fixed to theback plate; a seat plate hinged to said back plate and adapted to besecured to the seat section; a transfer pawl pivotally connected to theseat plate and having a large notch in its lower edge, undercutinwardly, to engage said latching finger when said plates are in sofaposition; a disengaging tumbler pivotally mounted on said pawl to swingdownwardly adjacent to'said pawl notch and having a downwardly opennotch with a carrying portion to register with the inwardly undercutportion of said. pawl notch, and an undercut throw-out portion toregister with the outer portion of the pawl notch; a guard on saidtumbler extending inwardly across the throwout portion of the tumblernotch; a repositioning detent on the tumbler, on the opposite side ofthe tumbler notch from said guard, and extending downwardly below theedge of the pawl to be engaged by the latching finger when returningfrom bed-position; and means urging the notched portion of. the tumblerto swing below I the pawl notch.

MARTIN FOX. GEORGE F. HASSEL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

